Double-contact socket for electric lamps



April 24, 1928.

- 1,666,973 F. J. MILES ET AL DOUBLE CONTACT SOCKET FOR ELECTRIC LAMPS Filed Nov. 14. 1924 I 75 l ze g5' L #fa 42 'e4- a 3f. 22 23 37' a0 'v' 34 hy ATTORNEY Patented pr. 24, 1928,

UNITED* sTA'riazs-v PATENT- fOFFICE? FREDERICK J. MILES AND DONALD c. THoMEsoN, F NEWARK, NEW JERSEY, As-

sIGNoRsEY iviEsNE ASSIGNMENTS, To EUGENE sULL1vAN,'oE NEW YORK, N; Y. 'e

f DOUBLE-CONTACT SOCKET FOR ELECTRIC LAMPS.

Applicationiea November 14, 1924; AseiaiNo. 749,906.

Our invention relates to lamp sockets designed for use with small incandescent electric lamps provided with pins for engaging bayonet lock slots in the socket and having 5 two bottom contacts instead of the customaryv ring and single bottom -contactand more particularly our'invention'relates to sockets of this typeforuse withrlamps where vibration is'tpresent and where it` is necessary to guard against the lamp Lworking loose in the socket and more particularly for use on ve'-` hicles, such askautomobiles, and especially, y v g `Figure 3 is a 4verticaly section- `on the line for use in signal devices for such vehicles.

' The object of our 'invention is to provide a socket which will insure perfect contact and guard aga-inst the lampv working loose, thereby avoiding poor contact or acontactbecoming entirely separated, and also lto insure clean contacts. The further' object is to provide a construction having the least number of parts readily made and assembled'and which will duction. f

To accomplish our objects we havedesigned a socket lhaving only fourI parts, and in which screws, rivetsy and brazed or soldered joints are entirely dispensed with. These parts comprise a base plate of insulatingmaterial, a sleeve or socket member whichmay be of metal or insulating'` material and two bottom contactV members. The socket member is preferably atubular metal piece having.

two oppositely located bayonet lock slots entering from the top AVof the sleeve, ktwo oppositely locatedopenings or gaps at the; lower end of the sleeve and diametricallyl opposite to the bayonet Vlocky slots land projecting from the bottom of .the sleeve viii linelwitli the bayonet lock slots two lugs b'ymeans of 40 which the socket 'or sleeve is'clamped'to the `base plate. The bottomy contact members are identical in form and preferabl 7:each be J lingin a single piece stamped from s eet metal .and bent into' 'shape so asf-to presenty three elements;l first, the contact` end which is bent into S-shape and which ends proj ec'tthfrougli vthe gaps in the sleevev member; second, a clamping'element consisting o f twoflater'ally projecting lugs whichare lbent downward to 51"? pass Vthrough `slots in the base plate and againbent to clamp the contact piece in position; third, at theouter en dt-wo .upwardly progecting lugs' forNclamping/the' circuit permit extremely low cost of pro- Y A Y kand Figure 7 is a cross section'on the line Referring now to the wires, Al fifth piece mayl be Vprovided. in each socket, namely, a covering of insulating material on the under side o'f the base plate to'coverthe lugs ofthe sleeve and bottom contact pieces -and thereby prevent "anyfpos'- lsible short-circuit between the two contact `plates and the sleeve member of the socket.-

f In the drawing, Figure 1 is an elevation of the socket with the lampmounted therein and circuit wiresv connected between clamp-y ing lugs of the bottom contact members; Figure 2'is a top plan view ofthe socket;

3-3' of Figure 2; Figure 4 is a `bottom view with the eXtra insulatingplate partly broken away; Figure 5 a vertical section' through 7&0

Figure 2 taken-at right angles tothe line 3*3 showing the clamping lugs for lthe wire rconnections in the open position and a wireY 7 7 of Figure 6. Y I drawings, 10.1i1idicatesthe sleeveor socket member which Amay be of metal lor insulating material, but preferably f of vmetal,r and" having` vbayonet type slots asH indicated at 11 and 12, whichare adapted to receivethe locking pins 16 projecting laterallyfrom a collar 17 'on the basel of vlamp 15. The sleeve 10, at-the end which is seated uponfthe base plate 24, of insulating material, islprovided with two oppositely located gaps -20 and 21 yand preferably so located as to'be diametrically opposite to the bayonet slots, and projectingfromthe lower endof the sleeve in line with the two bayonet slots arelugs22 a'nd'23 which are inserted through slots'25 and 25 in the base plate and bent over "as 'shownin FiguresA 3 and 4to clamp thesleevey member V10 firmlyr uponthe base plate. yThe base'plate 20may be of any desired shape but preferablyl of the shape shown in Figures 2 and 4 and is provided in' addition lto the two centrally locatedr slots k25 Y and'25a, `above referred to, with two pairsof ioo 'similar slots, 33a, 341 and 34a, a vpair being Y located `at each endf'of the base plate Vand somewhat closer together than'the first mentioned slots.` These 'fslotsare for securing the contact membersfin. position as' herein-A afterreferred toA 'The base plate is also provided with holes to receive pins or screws whereby the same may be secured to any dcsired support-or fixture or within an automobile lamp chamber. The bottom contact members 26 and 27 arepreferably identical in shapejeach being stamped from one piece of sheet metal such as brass or copper, in the form of a lon@v narrow strip with four projecting lugs; tlie contact 26 at its midesection 29 being provided with two laterally projecting lugs 31 and 31a which are bent downward and two vertically projecting lugs 38 and 38a, and likewise contact 27 at its midsection is provided with two laterally projecting lugs 32 and 32a which are bent downward, and two vertically projecting lugs 39 and 39a. The lugs projecting from the mid sections 29 and 30 are bent downward for the purpose of passing same through the slots 33, '338, and 34, 3dr-u respectively, and are-of sufficient length to be bent over as indicated in Figure 4: so as to clamp the contact members in position on the base plate. The lugs at the ends of the contact members are bent upward prepared to receive a circuit wire, as will be presently explained. The inner end of the contact members 26 and 27 are preferably bent into approximately S- shape so as to present a contact surface at 28 as indicated in Figure 5 where the contact :buttons 18 and 19 projecting downwardly from the lamp base are` shown in position within the sleeve 10. The midesections of the contact plates have a rectangular bend so as to present two sections substantially parallel with the base plate but out of contact therewith, see Figure 5, and then have the upward bendV andreturn bends 27 and .26 which complete the approximate letter S-shape. The contact points 28 of the two Contact members are so positioned vertically within the sleeve 10', that when the lamp is inserted the bottom contacts 18 and 19 of the lamp will engage therewith before the pins 16, projecting from the collar 17, reach the locking ends of the bayonet-slots so that as the lamp is pressed further downward toward the locking position, the spring contacts 26 and 27 will be under considerable pressure tending to pushv the lamp upward y and holding pins 16 firmly within the bayonet-locks. `When thus inserting the lamp and applying pressure `to the spring con tacts, it will be readily observed that the act of bending the contacts will produce a relatively rubbing action between same and the Contact buttons 18 and 19, thus insuring clean contacts.V The purpose in having two openings or gaps 20 and V.21, .oppositely spaced and higher than the height of the contact springs 26 and 27, is not only to provide a clear entrance for the contact springs, but also-to guard against the springs making contact with the sleeve 10, and by having the slots opposite to each other, no mis take can be made in mounting the sleeve upon the base plate, since it makes no diiference which of the gaps are adjacent to the ends of the base plate upon which the contact plates are clamped. For the purpose of facilitating the attachment of conducting wires to the contact plates, holes 36 and 37 are provided at a, point about midway of the lugs 38 and 39, respectively, and when attaching a circuit wire the end is bared of insulation andinserted downward through such, hole and then bentunder and over the end of the plate and back bet-ween the lugs 38, 38a, and 3K9, 39j, `so that the bared end of,V the wire will be parallel with the cov-V ered'portion ofl the conductor as shown in Y Figures 5 and 6, and thereupon one lug as shown at 39 Figure 7, is bent down firmly against the conductor, a pair of ordinary pliers being employed for the purpose, and

then the second lug, 39a, isY similarlly bentKV over, overlapping the lug 39, completingY the joint as show n in cross section in Figure 7. This mode .ofjoining the wire tothe contact plate produces a long close Contact doing away entirely with the use -of screws,

or solder,V Y Y lVhen a socket is assembled it isprovided with a bottom insulating plate 35, which is held in position by small bolts as shown in Figures l and It,v and these bolts may beemx ployed for vrsecuring the socket in position uponl the fixture or within-a lamp chamber.

From the foregoing it may be observed that theconstruction of our improved lamp socket lis extremelyl simple and as above stated, comprises only four parts and does away entirely with screws, rivets, or soldered joints in the-assembly of thesocke't parts proper, and that the only screws, or

bolts employed are those/for securing the socket in position-upon the fixture or within the lamp chamber, andv it is also levident that this .form of socket will withstand ex'- treme jarring and considerable vibration without any liabilityof the parts `becoming loose in'such manner'as to' result in poor contact or broken circuit.k j

lVhat we claim is: 's

An electric lamp .socket consisting of five parts, a base member of insulatingmaterial having a plurality yof-'slots formed therein; a cylindrical sleeveV or socket member having at one end two oppositely located bayonetlock Vslots adapted ,to receive the laterally proj ecting` pins of a lamp base, two oppositely located ygaps atrthe other end yand positioned diametrically opposite to the bayonet-lock slots,` and two oppositely -located lugs positioned between said gaps and adapted to pass through slots in the base', and bent projecting into the sleeve member through said gaps,

each of said contact members bey1,066,973 v y 8 ing formed in one piece,`stamped from sheet metal and having the Contact end in the form of the letter S, lugs projecting from the midL section adapted to pass through slots in the base plate and bent over to clamp the Contact piece in position, and at the outer end having lugs for clamping a circuit wire thereto,

DONALD C. THOMPSON. 

